Tolerability of the Immersive Virtual Reality System Grail in Subjects Affected by Rett Syndrome

"The subjects experiment GRAIL virtual reality for three days, during which they deal with 4 different activities.~In the first activity subjects are required to ask over the treadmill in a snow environment.~in the second they are required to stand over the moving platform in a simulation of a boat pitch.~in the third they have to walk over a bridge with a slope. in the fourth the subjects are required to try so interact with virtual reality and to ski between snowman.~if it is possible, on the last day a gait analysis is executed"